Terrain maps still have to follow the rules that apply to all Q3A engine
maps. There’s only so much that you can allow to be seen at one time, or the
game starts slowing down. The good news is that the engine will only draw the
terrain triangles that are in the player’s PVS (potential visible set). It
doesn’t have to draw all the triangles in the terrain entity just because part
of the entity is in view.

At first, most of the usual bag of tricks that mappers use to create vis
blocking structures in architectural maps don’t seem to apply to terrain. But
that is not the case. If anything, you NEED to think of terrain in much the same
way as you think of buildings. You are still dealing with open spaces that could
be considered corridors and large rooms … even though they look like large
valleys.

In fact, it would be best to plan out the layout of your terrain
BEFORE
creating your height map. If you know you want to block vis, you can design your
terrain to work with vis blocking techniques and avoid the agony of having to go
all the way back to the start when you discover that your killer terrain map
lets you see too much at once.

If you want the player, even in spectator mode, to be able to fly everywhere
and see the whole world laid out below him … an unrestricted vista, so to
speak, you’re going to be much more limited. Every single triangle in the map
will essentially be viewable at any moment in time. However, if you’re willing
to place restrictions on your players - limit how high they can fly or climb,
you suddenly have more options for blocking player visibility.

First, the terrain entity is entirely detail content, so it doesn’t block
vis. That’s a key part of how this whole process works. Otherwise, vis time
would be measured in eras (not minutes or hours) and visdata size would be very,
very large.

To block vis in the terrain, start by creating simple
vis-blocking structures
out of caulk texture inside the forms of the terrain (they are not part of the
terrain entity). You can try to match the silhouette of the terrain, but in the
end, you may only end up complicating the visdata without gaining any real
benefit.

Next, and this is going to sound strange, build thin walls of caulk that
follow the divide line (where the terrain falls away on both sides) of the
highest mountains, buttes or hills. Only do this where you know that you will
not allow the player to move over or see over

that
part of the terrain (we’ll talk about clipping real soon).

Other Tips:

·

Sky Texture in Place of Caulk:
You sometimes want to apply the sky texture to some of the surfaces of the thin
walls used as vis blockers. This can remove some HOM effects. The caulk brushes
that block the vis around the bases in mpterra2 have sky texture painted on the
surfaces facing the base.

·

Hint Brushes:
Use these extremely sparingly and only after trying to solve the problem in
other ways. Hint brushes can add hours to vis compile times. Even so, they can
make a difference. One trick you can try is to put a horizontal hint brush at a
point about midway up the slopes of your terrain. It can add some additional vis
break points.

·

Adjusting Terrain:
Vis times totally depend on the placement of your vis blockers. Vis times are
not affected by modifying the terrain surfaces (terrain entities are detail
content, remember?). With that being said, you may want to modify the terrain to
allow you to more effectively position the vis-blockers.